Spike,
You mentioned Anguilla, Aruba, and Barbados. I have also been there.
Anguilla has beautiful beaches and is relaxing but is extremely quiet. There is really no "downtown" area. Food and lodging are quite expensive. The only activities would be on St. Martin/ St. Maarten, which you can boat back and forth to.
Aruba has a few more things going on ( especially casinos) but doesn't appear to have a lot more than the beaches and their resorts. I don't know Aruba real well. There are a few old fort ruins to see as well.
Barbados is a possible good choice. Nice beaches, and lots of things to do on the island.